Fall 2010 IAB
September 15 to 17

Ming C. Wu, UC Berkeley, Chief Scientist CITRIS; BSAC Co-Director

Nanoassembly and Nanofabrication

The synthesis of nanowires and nanoparticles has advanced in the last decade to a point where a vast range of insulating, semiconducting, and metallic materials are available for use in various sensors, electronics and optoelectronics applications. However, a persistent challenge has been the development of a general strategy for the manipulation of individual nanowires and nanoparticles. In this talk, we present a novel technique for parallel assembly of nanowires and nanoparticles using optoelectronic tweezers (OET). Several examples will be presented. The first is the integration of III-V microdisk lasers on silicon waveguides for silicon photonics applications. Another example is the assembly of red, blue, and green nanowires on CMOS drivers for color displays. The trapped nanowires and nanoparticles can be selectively immobilized by increasing the electrical bias voltage. This mechanism, called NanoPen, has been used to pattern densely packed gold nanoparticles for surface-enhanced Raman spectroscopy (SERS). Enhancement factor greater than 107 and pico-molar sensitivity have been measured. Finally, we will conclude by a top-down nanofabricated optical transformer that can further boost up local field to increase the sensitivity of SERS.